1. The problem statement, all variables and given/known data For any positive integern, let U(n) be the group of all positive integers less than n and relatively prime to n, under multiplication modulo n. Show the the Groups U(5) and u(10) are isomorphic 2. Relevant equations 3. The attempt at a solution any 2 cyclic groups of the same size have to be isomorphic. For the answer to this problem should i do out a caley table for both groups to show they are cyclic? is this enough along with my statement? i guess what im saying is...does the question ask me to prove that 2 cyclic groups of the same size are isomorphic?